Department of Information Technology, P.R.M.I.T& R Badnera, India

Transcription

1 Volume 5, Issue 4, April 2015 ISSN: X International Journal of Advanced Research in Computer Science and Software Engineering Research Paper Available online at: Special Issue on Impact of Technology on Skill Development Conference Held at IETE Amravati Center, Maharashtra, India The Effectiveness of Request Redirection for Web Services 1 Prof. Preeti V. Dudhe, 2 Rachana N. Sawade 1 Assistant Professor 2 Student Master of Engineering, 1, 2, Department of Information Technology, P.R.M.I.T& R Badnera, India Abstract It is becoming increasingly common to construct network services using redundant resources geographically distributed across the Internet. Networks are a prime example. Such systems sends client requests to an appropriate server based on a variety of factors-- e.g., server load, network proximity, cache locality--in an effort to reduce response time and increase the system capacity under load. This paper introduce a heavily loaded application can sometimes crash due to transactional overload. An application can be deployed on multiple servers. This application implements a redirection server which analyzes the workload on each server and maintains a load database. Depending on the workload on the servers the new work will be allocated and excess load is avoided for smooth performance, hence the concept of request redirection is required. To explain the concept of redirection we have choose the example of ATM banking. Here a thin client is making a request which is pass on to the visa server which in turn analyze the request and then redirects it to the particular bank server. The bank server then handle the request and return the processed information back to visa server, which finally sends it to user. Index Terms Redirection, Server load, Network proximity, Cache locality. I.INTRODUCTION The explosive growth of traffic on the World Wide Web is causing a rapid increase in the request rate to popular Websites. This site can suffer from severe congestion, especially in conjunction with special events; the administrators of popular sites constantly face the need of improving the capacity of their Web-servers to meet the demands of the users. One approach to handle popular Web sites is based on the replication of information across a mirrored-server architecture, which provides a list of independent URL sites that have to be manually selected by the users. A more promising solution is to rely on a distributed architecture that can route incoming requests among several server nodes in a user-transparent way. This approach can potentially improve throughput performance and provide Web-server systems with high scalability and availability. However, a number of challenges must be addressed to make a distributed server cluster function efficiency as a single server within the framework of the HTTP protocol and Web browsers. In this paper we describe and discuss the various approaches on routing requests among the Web-server nodes. We analyze the efficiency and the limitations of the different techniques and the tradeoff among the alternatives. The scope of this paper is not to describe the detailed technical features of each approach, for which we refer the reader to the appropriate literature. Its aim is rather to analyze the characteristics of each approach and its effectiveness on Web-server scalability[1]. In today s world, more or less, every activity belongs to internet. The increase of E-Commerce has leads many businesses to carry out the most of their day-to-day business online transaction on data. As a result of the popularity of the web, providers of web sites and storage space providers want to ensure the availability of access to information for their users and the guarantee that requests are processed as quickly as possible [2]. Every human activity, business activity etc is completely or partially dependent on the computer and on computer network. The most common one we perform is of banking transaction. No one likes to stand in a queue for withdrawing their money. So the concept of ATM was introduced. It eased the work to some extent. But this ease was short lived as the number of ATM users grew exponentially every year. With this their arouse the need to open more and more ATM hereby increasing burden on banks. Then came on to develop such a centralized system which can connect various banks throughout the world, thereby reducing burden on the banks. With this new functioning arouse the need of redirection. The ATM all over the world are now connected to some central servers that redirects the request to particular bank servers and then act as connection link between the banks and clients.this has led to big technological boom in banking sector. 2015, IJARCSSE All Rights Reserved Page 234

2 II. LITERATURE REVIEW responsibility of Netscape browser to randomly chose one of these when user accessed This approach is not useful because it is not scalable. The key concept of this paper is basically request redirection. If redirection is considered in abstract sense then it is basically diverting the request to some other location. There are various form of redirection implemented on internet. The various forms of redirection are implemented for various types of applications and various types of needs. It is very powerful tool which is mostly needed to meet the various application requirements, like to maintain load to handle different request types, to optimize resource utilization etc. We are also required to know of the various technology used to implement the redirection concept. The various theoretical back ground required to know before concentrating on the paper development are described as below. A. Definition of Redirection Redirection is basically the process of diverting the request to a particular location and identifying the request. The server identifies the request type based on the defined parameters and the request to the appropriate server and vice versa. The parameters for identifying the request can be IP address, request type, some id etc. Clustered server organization is preferable to multiple independent mirrored-servers because it maintains a single interface to the users and has the potential to be more scalable, fault-tolerant and better load balanced. Requestredirection occurs over distributed sets of servers, minimizing redirection cost. B. Need of Redirection Today we perform various human activities; There are various reasons to do redirection. On the computer network redirection mechanism is very common and is applied in a number of situations: When a single server passes the request to many other servers. Redirection is primarily needed for the load balancing. For popular websites, it is not possible for a single machine to serve all the requests. So several servers are in operation simultaneously, sharing the load. Redirection is also needed when the website has been shifted. Similar domain names, moving a site to a new domain, Logging outgoing links short, meaningful, persistent aliases for long or changing URL s. C. Method of Redirection Once a server is chosen, this involves how to do the redirection. Redirection can be done at various levels: 1.Application level, using HTTP redirect 2. IP level 3. Using DNS [3] DNS- based approaches There is a single name used for the website. The client will ask DNS server for the IP address of the server. At that time, DNS server can choose an appropriate mirror and return its IP address. All mirrors have different IP addresses. Disadvantages: The major problem with this approach is caching. The DNS responses are coached by intermediate DNS servers and by the client also. So for the time a response is cached, all the requests using that will go to the same mirror. As a result, that mirror may get overloaded. So this allows only a coarse grained redirection. The authority name server has only a limited control over caching. Another obvious disadvantage is that it increases the load on DNS server. Dispatcher-based approaches In this approach, there is a central server called dispatcher which receives all the requests and then redirects the requests to appropriate server replicas. The dispatcher has a single IP address and identifies individual servers through some other address. In this approach also, there can be redirection at different levels. The possibilities depend on whether all replicas are on a LAN or are spread on a WAN. Server-based approaches In this approach, one of the mirrors, on getting an HTTP request, may decide to redirect the client to another mirror. Again, the redirection may happen at different levels: IP level with packet rewriting or at HTTP level. But it is generally done at the HTTP level. This approach is used along with another approach like DNS-based redirection. DNS-based redirection provides coarse grained redirection and this approach provides the fine-grained redirection if required. [4][5] III. SYSTEM ANALYSIS & DESIGN The system is divided into three modules, these modules are: Thin client Central server Bank server Client Side approaches In this approach, it is the responsibility of client (typically a browser) to choose a server out of the available mirrors. Earlier, Netscape had several server names www1, www2, www3.. And it was Fig1: Working Model of System Design 2015, IJARCSSE All Rights Reserved Page 235

3 A. Thin client Server side It is nothing but the ATM machines or user interfaces, Client side it is called as thin client because, it has no database or lot of request handling programs. It only consists of some user interfaces so that the user can interact and then transforms the requests into packets to transmit it to the central server ATM Working ATM cards use processors to connect to their various ATM networks. when someone swipes Or insert a debit card or credit card it asks for a pin number. So ATM machine at that time will dial a toll free number to begin the authorization process. ATM will be re-programmed with the TID(terminal ID number) that will identify it on our processor so the network will allow the transaction to complete.this TID along with other identifying information lets the cardholder bank know that the transaction is taking place on your ATM. If there are sufficient funds in the ATM cardholders account for the withdrawal request, the transaction will be completed. The ATM receives the authorization and dispenses the cash requested. Design of Thin Client Like if we consider that whenever we have to use ATM we have to first insert Acc no. and PIN. This is a general format diagram where we will pass on the information and then will click the button to login. On a general basis these two parts can be performing the following functions, the client side will accept the request from the clients change it into some form and add some information to it and then pass it over to other side which will analyses the information and then pass it over respective bank servers and finally will take response from bank servers and give it to client side to hand it over to the clients. Client Manager This part of the central server has the basic job of accepting the packets from client side, add some more information to it, generate a thread and then pass it onto the server manager. Now let us look into details of its function: The client manger is basically responsible for connection to the client/atm. Creating a socket for connection. Receiving and sending data from the socket for that particular connection. Identifying the particular bank. Ask the server manager to create a dedicated connection with the bank. Sending and receiving of data. Working Of the Client Manager B. Visa Server Fig3: Working Model of client manager Fig2: Working Model of Visa Server The central server plays the main role. This central server has to perform the job of connecting link between client and various bank servers. This server has to basically receive the request from client and send it back to bank server and then take request from bank server and send it to clients. Thus we think that central server performs the main job of redirection, so it can be broadly classified as: The main work of the client manager is to handle client side of working, for this it will require to sense a client and establish the connection. So for this particular purpose,the client server will be continuously listens the connections for the presence of the client, now if a client is found then it will establish a socket so that it can receive information in the form of packets. Now the next task is to identify the bank for the packet which has come. this is problem, as there are many ATMs and many banks, how will it recognize that the particular is for which bank. Now the standard 2015, IJARCSSE All Rights Reserved Page 236

4 solution to this problem which modern ATMs follow is that every card has particular id and few digits. So the client manager identifies the bank id. Now it will ask server manager to establish connection with respective banks server,and further packets are received and taken. Server Manager This server manager basically establishes the connection with bank server and send the packet of information. The basic requirements of the server manager are as follows: Maintain the bank server information Establish the connection with the bank server Maintain connection status information Generate commands from the received packets Working of Server Manager The server manager as the name suggest is mainly responsible for maintaining the server side connections and information. Now whenever the client manager asks the server manager to establish a dedicated connection with the respective bank it first has to check number of things. So in order to establish the connection we require the IP address and port numbers, so we can store the IP address of bank we can easily establish a connection. For this purpose a database is maintained by the server manager, which mainly consists of information like banks name, its IP address,its port number, connection is established or not etc. Now when the central server is started this server manager looks into its data base to find which all banks it can connect and then try establishing connection with each on of them. Then create and maintain server connection status information. C. Bank Server Bank server it is console type application. It is connected to database, it has request handler to receive the request. The bank server content all information about the client while it connected to main server. It contents the client account id number, pin code, acc no; name..etc such type of information. Goals of bank server: Banking system comprise a host computer and at least one portable terminal The terminal provide arrange of banking service over an connection to the host bank computer During a banking mode of operation control reside in the host bank computer The borrowing raising or taking up of money. IV. IMPLEMENTATION AND TESTING In multithreading multiple threads are created for each program so that first processing is achieved. Our main focus is on client side. There are multiple clients sending multiple requests which are received by the main server and the main server will create the thread of request and send it to the particular database depending on the request. The main modules are: Bank Server Main Server ATM Server We have various banks having their own database which stores the information about the customer. Also, there is one bank server used for redirection purpose. There are many databases having the information of particular bank. There are various ATM clients sending the request to the main server. The associated threads are created by the server and then forwarded to the specific bank database. In the ATM interface we start by entering the bank id along with valid password through the login form. The banks are identified on the bases of this bank id. First two digits are required for identifying the particular bank and the rest is account number of customer. The identification numbers of banks are as follows: SBI-99 ICICI-88 HDFC-78 If the password is not valid it will give error and you have to enter the right password. After Login the customer can perform his transaction effectively. The customer can withdraw amount, transfer money change the pin, checking balance. Elements of Architecture: A. ATM Clients These are the ATM customers which send their ATM request for their particular ATM services. Now this ATM request includes: Log in Log out Withdrawing money Checking balance Money transfer Change of pin B. Main Server Whatever request is given by ATM clients its associated threads are created inside the main server. These threads are redirected to the respective banks. Also, the ATM client can send many request at a time out of that, only one request are forwarded and rest are blocked. These threads handovers the request to the respective bank database and it get disabled. C. Bank Server The request forwarded by main server in the form of threads is received by bank server depending on the status of the bank database, the query is fired. D. Bank Databases It includes database of SBI, ICICI and HDFC banks. It consists of the table Acc Master having the following fields: Name Account number Password Balance Enabled Credit limit 2015, IJARCSSE All Rights Reserved Page 237

5 V. CONCLUSION Prof. Miss. P. V. Dudhe Author is In this paper we have presented a system which sends Assistant Professor with Department the request to the appropriate server in to reduce response of Information Technology, time and increase the system capacity under load. A P.R.M.I.T&R, Badnera heavily loaded application can sometimes crash due to transactional overload. An application can be deployed on multiple servers. This application implements a redirection server called Visa server which analyzes request and sends Miss. R. N Sawade Author is Student to the server and maintains a load database. Depending on with Department of Information the workload on the servers the new work will be allocated Technology, P.R.M.I.T&R, Badnera and excess load is avoided for smooth performance, hence the concept of request redirection is required. ACKNOWLEDGMENT I take this opportunity of thanking my guide Prof. P. V. Dudhe, Assistant Professor Department of Information Technology Engineering, P.R.M.I.T&R, Badnera for her indispensable guidance, generous help, perpetual encouragement, constant attention offered throughout in preparation of this paper. REFERENCES [1] Valeria Cardellia, Michele Colajanni, Philip.S. Yu Dynamic Load Balancing on Web Server System, Publidhe by IEEE Internet Computing /99. [2] L. Garber. Technology news: Denial-of-service attacks rip the Internet. Computer, 33(4):12-17, Apr [3] Limin Wang, Vivek Pai and Larry Peterson, The Effectiveness of Request Redirection on CDN Robustness USENIX Association 5th Symposium on Operating Systems Design and Implementation [4] Ankush P. Deshmukh, Prof. Kumarswamy Pamu, Applying Load Balancing: A Dynamic Approach, International Journal of Advanced Research in Computer Science and Software Engineering, Volume 2, Issue 6, June 2012 [5] D. Andresen, T. Yang, V. Holmedahl, and O. Ibarra. Sweb: Towards a scalable world wide web server on multicomputers, 1996 [6] P.Barford M. Carvello Genrating representive Web Workload for network and sever performance evaluation, Proc of ACM Sigmetic 98,Madsion, WI, pp ,june , IJARCSSE All Rights Reserved Page 238